﻿using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace TaskLiskFullscreen
{

    public class KeyboardHook : IDisposable
    {
        private const int WH_KEYBOARD_LL = 13;
        private const int WM_KEYDOWN = 0x0100;
        private const int WM_KEYUP = 0x0101;

        private IntPtr _hookId = IntPtr.Zero;
        private bool _winPressed = false;

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);

        private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);

        private LowLevelKeyboardProc _proc;

        public event Action OnWinJPressed;

        public KeyboardHook()
        {
            _proc = HookCallback;
            _hookId = SetHook(_proc);
        }

        private IntPtr SetHook(LowLevelKeyboardProc proc)
        {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule)
            {
                return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
            }
        }

        private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
        {
            if (nCode >= 0)
            {
                int vkCode = Marshal.ReadInt32(lParam);

                if (vkCode == (int)Keys.LWin || vkCode == (int)Keys.RWin)
                {
                    if (wParam == (IntPtr)WM_KEYDOWN)
                        _winPressed = true;
                    else if (wParam == (IntPtr)WM_KEYUP)
                        _winPressed = false;
                }
                else if (vkCode == (int)Keys.J && wParam == (IntPtr)WM_KEYDOWN && _winPressed)
                {
                    OnWinJPressed?.Invoke();
                    return (IntPtr)1;
                }
            }

            return CallNextHookEx(_hookId, nCode, wParam, lParam);
        }

        public void Dispose()
        {
            UnhookWindowsHookEx(_hookId);
        }
    }
}